Hazardous Area Guide for ATEX & IECEx - Triple i (2024)

The Hazardous Area Guide for ATEX & IECEx is your go-to resource for understanding and navigating the complexities of hazardous area classifications. This guide covers critical aspects of ATEX and IECEx standards, detailing the Zones and Groups that define explosive atmospheres. Whether you’re responsible for safety compliance or managing facilities in hazardous locations, this guide provides essential insights and the latest regulatory information to help you maintain safe and compliant operations.

Typical Equipment Marking for Gas Atmospheres

Hazardous Area Guide for ATEX & IECEx - Triple i (1)

Typical Equipment Marking for Dust Atmospheres

Hazardous Area Guide for ATEX & IECEx - Triple i (2)

Gas Zones

Gas ZonesDefinitionATEX CategoryEPLRequired Protection
MethaneMines with methane and dust. Equipment remains energised in explosive atmosphere.M1MaTwo Faults
MethaneMines with methane and dust. Equipment is de-energised in explosive atmosphere.M2MbSevere Normal Operation
Zone 0Explosive atmosphere present continuously or for long periods, frequently.1GGaTwo Faults
Zone 1Explosive atmosphere is likely to occur under normal conditions, occasionally.2GGbOne Fault
Zone 2Explosive atmosphere is unlikely to occur under normal conditions, short periods.3GGcNormal Operation

Dust Zones

Dust ZonesDefinitionATEX CategoryEPLRequired Protection
Zone 20Explosive atmosphere present continuously or for long periods, frequently.1DDaTwo Faults
Zone 21Explosive atmosphere is likely to occur under normal conditions, occasionally.2DDbOne Faults
Zone 22Explosive atmosphere is unlikely to occur under normal conditions, short periods.3DDcNormal Operation

Zones of Use

Explosive Atmospheres

Hazardous Area Guide for ATEX & IECEx - Triple i (3)

Enclosure Ingress Protection (IP) Level

Enclosure Ingress Protection (IP) Level: To EN/IEC 60529
First Number (Solid objects / dust)Second Number (Water)
0No protection0No protection
1Objects > Ø50 mm1Vertically dripping water
2Objects > Ø12.5 mm2Vertically dripping water with enclosure tilted by 15°
3Objects > Ø2.5 mm3Sprayed water up to 60° from the vertical
4Objects > Ø1.0 mm4Sprayed water from all directions
5Dust protected5Water jets
6Dust tight6Powered water jets
--7Temporary submersion less than 1m depth
--8Extended submersion greater than 1m depth

Ambient Temperature Range (Tamb)

Tamb = Temperature relating to the immediate surroundings of the equipment (assumed to be -20°C to +40°C, unless stated).

Protection Concept – Electrical – Gas

Type of Protection (electrical - gas)Reference
General RequirementsEN/IEC 60079-0
Flameproof - Ex d / da / db / dcEN/IEC 60079-1
Purge/Pressurised - Ex p / pxb / pyb / pzcIEC 60079-2
Quartz/Sand Filled - Ex q / qb / qcEN/IEC 60079-5
Oil Immersion - Ex o / ob / ocEN/IEC 60079-6
Increased Safety - Ex e / eb / ecEN/IEC 60079-7
Intrinsic Safety - Ex i / ia / ib / icEN/IEC 60079-11
Non Sparking - Ex nA / nC / nLEN/IEC 60079-15
Encapsulation - Ex m / ma / mb / mcEN/IEC 60079-18
Optical Radiation - Ex op is / op sh / op prEN/IEC 60079-28
Trace Heating Systems - Ex e / Ex 60079-30-1EN/IEC 60079-30-1
Special Protection Ex sEN/IEC 60079-33
CaplightsEN/IEC 60079-35-1
Controlled Spark Duration Power-iTS 60079-39
Process SealingTS 60079-40
Flame ArrestersEN 16852
Diesel EnginesEN 1834-1,2,3

Protection Concept – Electrical – Dust

Type of Protection(electrical - dust)Reference
General RequirementsEN/IEC 60079-0
Enclosure - ta / tb / tcEN/IEC 60079-31
Purge/Pressurised - Ex p / pxb / pyb / pzcIEC 60079-2
Intrinsic Safety - Ex i / ia / ib / icEN/IEC 60079-11
Encapsulation - Ex m / ma / mb / mcEN/IEC 60079-18

Protection Concept – Non-Electrical

Type of Protection(non-electrical) (gas & dust)Reference (ATEX only)IECEx
General RequirementsEN 80079-36IEC / ISO 80079-36
Flow Restricting Enclosure - frEN 13463-2-
Flameproof - dEN 13463-3-
Constructional Safety - c / hEN 80079-37IEC / ISO 80079-37
Control of Ignition - b / hEN 80079-37IEC / ISO 80079-37
Pressurisation - pEN 60079-2-
Liquid Immersion - k / hEN 80079-37IEC / ISO 80079-37

Gas Groups

Gas GroupsGasses are classified according to the ignitability of the gas/air mixture as defined in EN/IEC 60079-20-1
IIAAcetic Acid, Acetone, Ammonia, Butane, Cyclohexane,Propane, Gasoline (petrol),Methane (natural gas, non-mining), Toluene, Xylene. Methanol (methyl alcohol), Propane-2-ol (iso-propyl alcohol)
IIBGroup IIA gases plus, Di-ethyl ether, Ethylene, EthanolMethyl ethyl ketone (MEK), Propane-1-ol (n-propyl alcohol)
IICGroup IIA and IIB gases plus, Acetylene, Hydrogen

Dust Groups

Dust GroupsDusts are classified by the types of material that make up the dust
IIIACombustible Fibres and Flyings
IIIBGroup IIIA dusts plus, Non-Conductive Dusts
IIICGroup IIIA and IIIB dusts plus, Conductive Dusts

Equipment Groups

Equipment GroupDefinition
Group IElectrical equipment intended for use in mines susceptible to fire damp
Group IIElectrical equipment intended for use in explosive gas atmospheres
Group IIIElectrical equipment intended for use in explosive dust atmosphere

Temperature Class (T Class)

TemperatureClass (T Class)Highest temperature achieved under the most adverse equipment rating and heating conditions. (Flashpoint temperature of some gases)
T1: 450°CAmmonia (630°C), Hydrogen (560°C), Methane (537°C), Propane (470°C)
T2: 300°CEthylene (425°C), Butane (372°C), Acetylene (305°C)
T3: 200°CCyclohexane (259°C), Kerosene (210°C)
T4: 135°CDi-ethyl Ether (160°C)
T5: 100°C-
T6: 85°CCarbon Disulphate (95°C)

DISCLAIMER– this service is provided without warranty or claim of fitness for any purpose. Triple i takes no responsibility for the accuracy of the figures provided and customers should use this service at their own risk.

Hazardous Area Guide for ATEX & IECEx - Triple i (2024)
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